27
26
3. Reading Ratios
Question:
30/20 = 60/x
Solution:
Align 30 on the outside scale with 20 on the inside scale. At this
time, the answer of 40 can be read from the inside scale
corresponding to 60 on the outside scale. In addition, the ratio of
the value on the outside scale to the value on the inside scale is
30:20 at all positions on the scales.
4. Determining Square Root
Question:
What is the square root of 225?
Solution:
Rotate the scales so that the value on the inside scale
corresponding to 22.5 on the outside scale is equal to the value on
the outside scale corresponding to
X
10
on the inside scale, and read
off the answer of 15 at that location.
